After following false leads for nine years, police working the Brown's Chicken & Pasta slayings found themselves listening to a woman who knew a detail of the killings that had never been revealed to the public.

During the slayings, sources say the woman told police, one of the victims vomited.

That unsettling detail put investigators onto the trail of two suspects, who were arrested Thursday, and raised hopes that there could soon be a conclusion to a saga that began Jan. 8, 1993.

Late Friday, authorities were still questioning two old Fremd High School friends, one a former Brown's employee. Palatine police, who have said they would not discuss the case until charges are filed, had scheduled a news conference for 3 p.m. Saturday.

For nine years, investigators have faced charges that they mishandled the hunt for whoever shot seven people, then mopped up the bloody scene.

But time also was good to police.

The years that elapsed since the crime were enough to allow someone to overhear another person talking about the killings--and for forensic science to improve dramatically.

The vital DNA evidence eventually tying one of the suspects to the crime scene wasn't isolated until new tests were begun in late 1999. The source of the DNA was a chicken dinner that had been left in a restaurant trash can and, wisely, preserved by investigators. In 1993, the science was not good enough to find DNA in the trace of saliva on the food.

The developments in recent days have raised the expectations of a breakthrough for investigators; for a community haunted by the murders even after the restaurant itself was demolished a year ago; and, most of all, for the families of those slain.

Even with the two suspects in custody, Emmanuel Castro, father of victim Michael Castro, said he felt little comfort. "There's no relief. Michael is not coming back," he said. "The more we talk about it now, the more difficult it is."

Healing has not been easy for the village of Palatine either. "I don't think the uneasiness has ever really left the community," said Mayor Rita Mullins, a staunch defender of her Police Department in the face of heavy criticism. "We, the village of Palatine and the Palatine Police Department want more than anyone to tell the world that we have a conclusion to this horrible, tragic incident."

The case began to thaw when a tipster told police that she overheard another woman say that her former boyfriend and another man committed the crime.

That woman apparently knew about the murders almost from the beginning. According to a law-enforcement source, she provided the former Brown's employee an alibi when they interviewed him within weeks of the shooting. She said she could vouch for his whereabouts the night of the murders.

After overhearing the woman speak of the killings in recent months, the tipster tried to talk the woman into going to the police. Fearful of the man, she didn't, and the tipster finally did so herself.

Police then went to the former girlfriend. Initially skeptical, they took her seriously when she revealed the key detail that had never been made public.

In mid-April, police took DNA samples from the two men. About 10 days ago, the Illinois State Police crime lab got a match with a piece of a chicken dinner that had been found in the otherwise cleaned restaurant.

Despite criticism of many aspects of the investigation, forensic experts credited authorities with having the presence of mind to save and freeze the chicken samples for tests that were still on the drawing board.

"It shows they were pretty forward-thinking, whoever decided to save it," said David Coffman, supervisor of the State of Florida's DNA database. "Ten or even seven years ago, we would never have thought to test a piece of food that was half-eaten. We wouldn't have had the technology to get a result."

When Palatine police found the half-eaten chicken dinner, the technology for identifying who ate the meal was still poorly developed, experts say. PCR, a method for amplifying tiny amounts of DNA evidence, had been invented only in 1985; the techniques used today for reliably coding and analyzing genetic evidence were first proposed in 1992.

It was clear to some in law enforcement that DNA fingerprinting would soon become a powerful crime-solving tool.

But the crucial technology was gradually refined and gained acceptance only in the years after the Brown's murders.

Samples the size of a pinhead

Before PCR became widely available, tests of saliva or blood typically required a stain at least the size of a dime, experts say. But PCR can make almost unlimited copies from minute traces of DNA, allowing police to work with samples the size of a pinhead.

According to police, authorities in late 1999 or early 2000 began looking into testing the chicken meal left in the restaurant.